46 KEEGAN : THE CHEMISTRY OF SOME COMMON PLANTS. 
might surely devote a few minutes’ cogitation to the matter. Ther@ 
very atmosphere in which the plant breathes, especially if the sun be ; 
high and strong, seems redolent of ammoniacal odours ; and this 
fact affords a tolerably safe presumption that it is rich in nitrogenous 
matters. In May, the fresh leaves contain about 54 per cent. protein, 
which is a very large proportion. When the herb is distilled with — 
water, carbonate of ammonia and formic acid are obtained—bodies — 
‘which indicate the presence of nitrogenous and resinous matters, anda 
were at one time fastened on as imparting acridity to the sting-fluid; 
but a more searching investigation has shown that they have got little 
to do with it, and that this inflammatory property is not due to an — 
-alkaloid nor to any volatile body, but to an unorganised ferment 
derived from the albumen of the very large gland which occupies _ 
the greater portion of the stinging hair. ‘The extreme depth of its 
verdure is owing to the large amount of carotin which the plant © 
Se larger than any other common plant. According to 
, at the fl g peri d the dry leaves contain 171°7 mgrms. — 
per loo piel or over a ya/gp part of their weight, and it darkens — 
the natural tint of the shicrcabyll In fact the benzene extract of 
the leaves gives the deep blue reaction of carotin with sulphuric acid 
-at once ; no other leaf known to me does this. ‘There is no alkaloid — 
in the leaves, but they contain a curious glucoside which, boiled with 
acids, yields a dark brown, almost black, tarry substance which is 
soluble in alkalies, and is not a derivative of benzene. There is very 
little tannin in the plant ; what there is seems to be viridinic acid, aS 
the yellow decoction left to dry in the air yields a fine emerald green 
residue which is turned red by sulphuric acid. About } per ‘cent. : 
fat, 7 or more per cent. resin, and much mucilage with stale: nitrate, — 
and oxalate of calcium, complete the list of constituents of a higl ve 
remarkable herb. 
Ribwort (Plantago lanceolata). ‘This plant contains protein — 
{about 2°65 per cent. in May), sugar, resin, very little fat, much 
carotin, viridinic acid, and a bitter principle which boiled with aci 
the liquid on filtering and cooling deposits an azure blue substance 
which is not indigo. 
rass. For the account of a mere rough qualitative analy: 
it would be invidious to mention any particular species of the 
one third is about the middle of May composed of amides 
amido-acids; and it is these bodies which are supposed to 
Nat 
